A personal, guided tour to the best scoops and stories every day in The Wall Street Journal, from Editor in Chief Gerard Baker.

A U.K. court ruled Thursday that the British government can’t trigger negotiations to leave the European Union without a vote from Parliament, dealing a major blow to Prime Minister Theresa May’s plans. The U.K. government said it was disappointed by the judgment and that it would appeal the ruling, which could force the government to get parliamentary approval to trigger Article 50, the formal mechanism that begins a two-year window for exit negotiations. Stocks gained and the pound...